Automatic fire alarm



Aug. 24,1926.

W. A. ELLIOTT AUTOMATIC FIRE ALARM Filed 'April 22 1924 Patented Aug. 24, 1926. f

UNITED vSV'I'ATEVS WILLIAM A ELLIocrr, oFEas'r GRAND ronxs, MINn'Eso'ra.

.AUTOMATIC man ALARM.

'Application tiled April 22, 1924. i Serial No. 708,262.

The presentinvention relates to improvements m automatic ,fire alarms, and morey specifically to that type of alarm apparatus embodyingfin an .open circuit, a circuit closing device and an audible or visible signal device, the circuit closing device and si nal device being positioned atany suitable p ace with respect to one another.

The primary object ofthe invention is to provide an automatic fire alarm of the described character, embodying features whereby a circuit will be completed through the apparatus, as the resultant action of an ejecting explosive force.

Other ob]ects of the invention are toprovide a simple and ecient fire alarm whereby the working parts-thereof may bc encased', so as to not be affected byfire, prior to the completing of the-electric circuit, and one whereby a combustiblefuse for detonating an'explosive, carried by the alarm, may run to a point or points where fire is most likely to occur. f

Other objects and advantages of the invention will appear in the following detailedy description, taken in connectiony with `the accompan in drawing, forming a part of this speci catlon, and in which drawing,

Figure l is a longitudinal lsection taken through an alarm vcol'istructed in accordance with my invention, and showing the'interior mechanism` in a set position. Figure 2 is a view similar to Figure 1, and showingY the interior mechanism in a released or signalin position.

Figure 3 is an en arged transverse section taken on the line 3-3 of Figure 2.

Figure 4 is an enlarged transverse section taken on the line 4-4 of Figure 2.

Figure 5 is an enlarged fragmentary sectioi taken on the line 5-5 of Figure l, an

Figure 6 is an enlarged fragmentary section taken on the line 6-6 of Figure 2.

Referring to the drawing in detail, and wherein similar characters designate corresponding parts throughout the several views, the letter A designates an automatic lire alarm, comprising a box or casing B for encasing a circuit closer C and a release device D; the release device Drbeing operable through a combustible element E.

The box or casing B for encasing the mechanism of the alarm, preferably consists of a substantially dat, rectangular shaped metal boxbody 10 having a yremovable metal cover portion 11, for closing the open face thereof. This encasing of the mechanism will, in addition` to protecting the mechanism against `fire, prior yto the completing of the electric circuit, also protect themechanism from dust and the like, and maintain a dry atmospheric condition within thebox. A suitable number of openings l2 are provided inthe box body -10 for permittinor of electric conducting wires to enter the casing for attachment to the circuit closer C, and a single hole or opening 13 is provided for permitting of the combustibley element E to enter the casing for operative engagement with lthe released device D.

Referring to the circuit closer C, which is adapted forcompletinga circuit through the signal device 14, the same preferably embodies two spacedap-art stationary contacts 15 and 16, which are insulatively mounted on the inner face of the base 17 ofthe box body 10,' by combined fastening elements and binding posts 1 8. A contact arm 19 is pivotally mounted yadjacent one end to the stat-ionary contact 16,y by fa bolt or rlvet 20. A coil spring 21, having one end thereof secured to the base 17,'"and its otherend secured to the ycontact arm 19, is adapted for throwing the free end of the arm into contacting engagement with sta# tionary contact 15, when the armis released by the 4action of the release device D. A switch socket or stop 22 is secured tothe contact 15 in orderthat the arm 19 vwillbe stopped and held in contacting relation with the contact 15.

A connecting strip 23 may be insulatively mounted on the base 17 by means of combined fastening elements and binding posts 24. It canbe seen that by so providing the hiding posts 18 and 24, that the wires 25,

which lead to the signal device 14, and the wires 26, which are in circuit with a source of electric energy 27, may be readily connected to the alarm.

Referring to the release device D, the same consists of an arm 28 pivotally mounted intermediate its ends to the base 17 by means of a bolt or rivet 29, and having provided at one side of the pivot bolt, a projection 30 adapted yto releasably engage the free end of the contact arm 19. A combustion cup 31 for holding a small amount of explosive material, is positioned at the opposite side ot' the pivot 29, with its open end in abutting relation With a stationary combustion shoulder 32 secured to the base 17. This combustion shoulder is adapted to fully close the open end of the cup 3l, and also torni a stop ifor the arm 28 `which is normally held in a set position by means of a coil spring 33 which is secured at one end to the cup end ot the arm. and has its other end secured to the box body l0. An opening Bil is provided in the cup 3l ior permitting or" the coinbustible element E, which is preferably in the torni of a combustible fuse 35, to enter the cup and lie in contacting relation with the explosive contained therein.

The fuse 35 which extends exteriorly of the casing B, may be run to any desiied point or points Where lire is most likely to occur, and it desired, branch fuse lines may be connected with a main fuse line which is in communication ivitli the alarm.

It will thereitore be seen, that when the explosive ivithin the combustion cup 3l is exploded by the burning` ot the 'fuse 35, that the explosive torce which ejects from the open end ot the combustion cup, will act directly upon the combustion shoulder 32, and by forcing` the arm 2S against the action ot the spring 33, will cause the contact arm 19 to be released' and move to circuit completing relation with the stationary contact l5.

By so enclosing the explosive Within a metal casing, it vfill be maintained in an eilective condition against dampness or the like, which might tend to interfere with the successful operation of the alarm. It will also be seen that the combustion cup 3l may be readily refilled and the 'alarm reset, by merely daWing the arm 2S in a direction against the action o'tl the spring 33.

It is to be understood that minor changes in construction may be made, and that the apparatus may embody a plurality o'l" alarm devices and signal devices, connected in a suitable circuit, Without departing from the spirit or scope of my invention; but,

l claim l. An automatic tirm alarm comprising a casing, stationary contacts carried by said casing, a contact arm pivotally connected to `one of said stationary contacts, means for normally urging the contact arm into engagement with another of said stationary contacts tor completing a circuit therebetvveen, a release device for normally holding the contact arm in an open circuit position comprising an arm pivotally connected to said casing, a combustion cup for holding an explosive, carried by said ai'in, a combustion shoulder secured to said casing adapted to close the open end ot the cup and torni a top therefore, and a combustible fuse communicating with the explosive within said cup for discharging the explosive and releasing said contact arm.

2. An automatic tire alarm comprising a casing, stationary contacts carried by said casing, a contact arm pivotally connected to one of said stationary contacts, means for normally urging the contact arin into engagement With another ot' said stationary contacts for completing a circuit therebetween, an arm pivotally connected inten mediate its ends to said casing, a projection provided on said arm at one side ot' its pivotal point for releasably engaging the free end of said contact arm, a combustion cup for holding an explosive, carried by said arm at the opposite side ot the pivotal point, a combustion shoulder rigidly secured to said casing and adapted to close the open end ot the cup, means for normally urging the cornbustion cup into engagement with said combustion shoulder and a combustible fuse communicating with the explosive Within said cup tor discharging the explosive and releasing said contact arm.

VILLLXM A. ELLIOTT. 

